There has been known a motor comprising a rotor, a stator, a pair of bearings, and a motor housing. These components are configured as follows. The rotor includes a rotor member and a shaft on which the rotor member is fixed. The stator is disposed radially outwardly of the rotor member. The pair of bearings rotatably support both ends of the shaft. The stator is securely disposed inside the motor housing. Among the motors of this kind, there is a motor in which a bearing holder is mounted into amounting hole formed in a motor housing. The bearing holder is fixed to an outer ring of one of a pair of bearings. As a bearing holder mounting structure configured to mount a bearing holder in a motor housing in this type of motor, Japanese Patent Application Publication No. 2007-6592 (JP2007-6592A) discloses an example in which the bearing holder is mounted in the motor housing using a plurality of screws, for example.